The rapidly growing popularity of wearable devices will lead to a surge in volume of mobile traffic, Cisco is predicting.

Cisco forecasts that 578 million wearable devices will be in use around the globe by 2019, up from 109 million last year. That’s a fivefold increase, but the resulting mobile data traffic will increase by a factor of 18 — though most of that traffic will be channeled through smartphones, the networking giant claimed Tuesday in its annual look ahead at traffic trends.

Some wearables, like the upcoming Apple Watch, require using a smartphone to transmit data. But the devices on average already generate six times more traffic per month than a basic handset, Cisco said. Its high-end example of a wearable is a GoPro video cameras, which can generate about 5 MB of mobile data traffic per minute when live streaming.

Overall, there will be 11.5 billion mobile connections by 2019. Of those, 8.3 billion will come from personal mobile devices such as smartphones, tablets and laptops, which Cisco claimed will see a resurgence as they take on more features found in tablets.